mesa: Pure software accum buffer.

The existing implementation was already implemented on software, but relied
on the pipe driver to always support the R16G16B16A16_SNORM format. This
patch eliminates that, without prejudice against a future hardware-only
implementation.

It also avoids some of the short <-> float conversions, and only does a read
transfer of the color buffer on GL_RETURN if absolutely necessary.

1 files changed, 8 insertions, 5 deletions

diff --git a/src/mesa/state_tracker/st_cb_fbo.h b/src/mesa/state_tracker/st_cb_fbo.h
index 44fa9fe9a4..9a199550d9 100644
--- a/src/mesa/state_tracker/st_cb_fbo.h
+++ b/src/mesa/state_tracker/st_cb_fbo.h
@@ -30,10 +30,6 @@
 #define ST_CB_FBO_H
 
 
-#define DEFAULT_ACCUM_PIPE_FORMAT PIPE_FORMAT_R16G16B16A16_SNORM
-
-
-
 /**
  * Derived renderbuffer class.  Just need to add a pointer to the
  * pipe surface.
@@ -45,6 +41,13 @@ struct st_renderbuffer
    struct pipe_surface *surface; /* temporary view into texture */
    enum pipe_format format;  /** preferred format, or PIPE_FORMAT_NONE */
 
+   /**
+    * Used only when hardware accumulation buffers are not supported.
+    */
+   boolean software;
+   size_t stride;
+   void *data;
+   
    struct st_texture_object *rtt;  /**< GL render to texture's texture */
    int rtt_level, rtt_face, rtt_slice;
 
@@ -62,7 +65,7 @@ st_renderbuffer(struct gl_renderbuffer *rb)
 
 
 extern struct gl_renderbuffer *
-st_new_renderbuffer_fb(enum pipe_format format, int samples);
+st_new_renderbuffer_fb(enum pipe_format format, int samples, boolean sw);
 
 extern void
 st_init_fbo_functions(struct dd_function_table *functions);